Surgical introducer with guidance system receptacle

ABSTRACT

An introducer system for use with a navigation probe. The introducer system has an introducer and a probe retainer configured to selectively connect to the introducer. The probe retainer includes a receiver configured to receive a navigation probe shaft and limit movement of the navigation probe shaft in the lateral direction. A first clamp and a second clamp are connected to the receiver with the receiver located between the first clamp and the second clamp. Each of the first clamp and the second clamp is selectively engageable with respective portions of the introducer sidewall to hold the receiver at a fixed location relative to the introducer. The receiver, the first clamp, and the second clamp are configured to provide a visual path through the probe retainer and into the introducer passage.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/805,821, filed on Nov. 7, 2017, which is a continuation-in-part thatclaims priority to U.S. Provisional Application No. 62/418,507, entitledSURGICAL INTRODUCER WITH GUIDANCE SYSTEM RECEPTACLE, filed Nov. 7, 2016,and U.S. Utility application Ser. No. 15/372,890, filed Dec. 8, 2016,the complete contents of all of which are incorporated herein byreference.

FIELD OF THE INVENTION

The present invention relates to delicate tissue surgical retractorsystems for use in the brain or other tissue susceptible to retractioninjury.

BACKGROUND

A variety of different devices have been used to retract delicate tissueduring surgical procedures. One such device is illustrated in UnitedStates Patent Publication Number 2010/0010315, which is incorporatedherein by reference. FIG. 1 of this publication illustrates a softtissue retractor system having a hollow retractor 100, and an introducer102 that is selectively inserted into the retractor 100. The retractor100 and/or introducer 102 may include a handle 104 to facilitatemanipulation and placement of the retractor system, and a lock to holdthe introducer and retractor together. The handle 104 is configured toconnect to a clamp 106, such as the standard surgical clamp 106 shown inFIG. 1 . The device in FIG. 1 (with some modifications) is commerciallysold as the “VBAS” device by Vycor Medical, Inc. of Boca Raton, Fla.

A retractor system such as shown in FIG. 1 is often used by insertingthe introducer 102 into the retractor 100 and locking it in place, sothe two can be moved and manipulated as a unit. The combined retractorsystem is inserted into the patient's body and moved to the surgerysite, and then the introducer 102 is unlocked and removed to permitaccess to the site through the retractor 100. When the unit is in place(either before or after the introducer 102 is removed), the handle 104may be locked to a clamp 106 to hold the retractor 100 in place.Surgeons using this retractor sometimes do not use a clamp to hold theretractor at the surgery site, and often manually manipulate theretractor to access different parts of the surgery site during thesurgical procedure. The retractor system and the retractor may bemanipulated by holding the proximal ends of the introducer or retractoror by holding the handle.

The device shown in FIG. 1 may have a transparent introducer 102 and/orretractor 100, and surgeons using such devices advantageously use thetransparent introducer and retractor to observe the underlying tissueand to visually guide the unit to the surgery site. While it has beenfound that visual guidance by looking through the introducer 102 is verybeneficial, it also has been found that some form of additional guidanceor navigation may be desired in some cases. For example, in some cases,surgeons have used a probe or guide wire (a narrow elongated rod) toguide the movement of the retractor system. In such cases, the probe isadvanced to the surgery site, and then the interlocked retractor systemis slid over the probe until it reaches the surgery site. This isfacilitated by the inclusion of a hole at the tip of the introducer thatfits around the probe. If the hole through the tip of the introducer isabsent, this method cannot be used. This type of system is described inUnited States Patent Publication Numbers 2008/0109026 and 2009/0048622,which are incorporated herein by reference. These references also showan alternative construction, in which the retractor is not locked to theintroducer.

It has been found that some surgeons using the above procedure may use aprobe that is integrated into a computer navigation system. For example,the probe may include a so-called “starburst” or the like, on theprobe's proximal end (i.e., the end opposite the distal end that isinserted to the surgical site). This and other navigation systems areknown in the art. For example, frameless navigation systems and othercomputerized guidance systems and methods are described in U.S.Publication No. 2001/0027271 (which is incorporated herein by referencein its entirety) and others, and are commercially available fromcompanies such as Medtronic, Inc., Stryker, BrainLab, AG, and GEHealthcare. As used herein, “computerized guidance” encompasses anymethod of guiding a device to or at a surgical site that relies oncomputer visualization and/or control.

United States Patent Publication Number 2010/0010315 briefly notes thepossibility of using stereotactic guidance or navigation in conjunctionwith a surgical retractor, but does not illustrate or describe thisprocedure or any apparatus for accomplishing this objective.Nevertheless, surgeons have been known to use a navigation probe“freehand” with a VBAS device such as shown in FIG. 1 . In such cases,the surgeon holds the navigation probe in place within the introducerwhile advancing the unit towards the surgery site. The tip of the probemay be placed in or near an opening through the tip of the introducer,but the opening through the introducer may be somewhat larger than theprobe tip and is oval, and does not hold the probe tip in any particularorientation. Such techniques can suffer from inaccuracy and displacementof the probe from the introducer tip, and it can be difficult to holdthe probe in place. Also, in some cases the probe tip may extendpartially through the introducer tip opening, which can risk damagingunderlying tissue. However, freehand use can be helpful to allowoccasional removal of the probe to provide an unobstructed view throughthe introducer of the underlying tissue.

While computerized surgical guidance systems are well-known, a number oflimitations exist with respect to their use with retractor systems, andparticularly with systems like those shown in FIG. 1 . For example,while some surgeons use computerized guidance to direct a probe to thesurgery site, and then slide the retractor system over the probe to thesite, the movement of the retractor may be somewhat imprecise and theprocess can be unduly cumbersome. This method also is not available ifthe retractor system does not have a through-hole that fits over theprobe (due either to the absence of a hole or a hole that is too small).In addition, the probe does not provide a view of the tissue throughwhich it is advanced, so there is no visual means to perceive and avoidcritical tissue (e.g., major blood vessels or nerves) when inserting aprobe before inserting a retractor/introducer system. Also, thesmall-diameter probe may sever delicate tissue cells, such as grey orwhite brain matter, rather than moving the cells aside and passingbetween them as would be expected to happen when advancing the retractorsystem.

United States Patent Publication Number 2013/0066154, which isincorporated herein by reference, shows examples of systems forintegrating a navigation probe into a surgical introducer. For example,FIGS. 1-6 of this publication show a navigation probe that is secured tothe inside of a pre-existing introducer by resilient means, such asrubber plugs or O-rings. Another embodiment uses a slip fit (e.g., FIGS.7-8 ), and still another embodiment uses an arm to hold the probe downinside the introducer (FIG. 9 ). Still other versions mount thenavigation device outside the introducer, to an arm that is connected tothe retractor assembly (FIGS. 10-11 ). While these systems may providesuitable performance, they also have certain potential shortcomings. Forexample, resilient plugs may slip in the presence of fluids and may bedifficulty to disengaged to remove the navigation device during surgery,a slip fit requires careful monitoring to ensure proper positioning, anarm as shown in FIG. 9 to hold the probe in place requires the probe tobe modified to include a surface against which the arm pushes, andlocating the navigation device outside the introducer complicates thecorrelation between the navigation device and the tip of the introduceror retractor.

United States Patent Publication Number 2012/0071748, which isincorporated herein by reference, shows another example of a system forintegrating a navigation probe into a surgical introducer. In this case,the probe is retained in a narrow channel through the introducer, andheld in place with a threaded locking screw. The locking screw adds anadditional potentially-removable part to the operating theater, andtherefore this reference adds a separate retaining device (see FIG. 7B)to prevent the locking screw from being removed. The locking screw alsocan be relatively difficult to manipulate, particularly when wearingsurgical gloves.

United States Patent Publication Number 2016/0015374, which isincorporated herein by reference, shows yet another example of a systemfor integrating a navigation probe into a surgical introducer. Thedevice shown in this publication holds the probe in a tube-like sheaththat extends distally into the introducer from the proximal open end ofthe introducer, and has a convenient single-throw clamp to lock theprobe in place. This device also optionally includes a mechanism toindicate when the navigation probe is fully seated in the introducer.While this device is useful to ensure greater accuracy and registrationbetween the introducer and the navigation probe, it may obstruct thesurgeon's view to some degree, and may make frequent removal andreinstallation of the navigation probe somewhat cumbersome as comparedto freehand use of the probe.

It has been found that there still remains a need to provide alternativeapparatus and methods for coordinating the use of guidance systems withsurgical introducers.

SUMMARY OF THE INVENTION

In one exemplary aspect, there is provided an introducer system for usewith a navigation probe having a navigation element and a navigationprobe shaft having a diameter and terminating at a distal probe tip. Theintroducer system includes an introducer and a probe retainer. Theintroducer has a sidewall extending along a longitudinal axis andforming an introducer passage extending from a proximal introducer endto a distal introducer end, the introducer passage being larger, in alateral direction that is orthogonal to the longitudinal axis, than thenavigation probe shaft diameter. The probe retainer is configured toselectively connect to the proximal introducer end. The probe retainerincludes a receiver configured to receive the navigation probe shaft andlimit movement of the navigation probe shaft in the lateral direction,and a first clamp and a second clamp, the first clamp and the secondclamp being connected to the receiver with the receiver located betweenthe first clamp and the second clamp, each of the first clamp and thesecond clamp being selectively engageable with respective portions ofthe sidewall to hold the receiver at a fixed location relative to theintroducer. The receiver, the first clamp, and the second clamp areconfigured to provide a visual path through the probe retainer and intothe introducer passage.

Each of the first clamp and the second clamp may be connected to thereceiver by a respective clamp arm, each clamp arm having an openingtherethrough, the opening being aligned with the introducer passage toform a respective part of the visual path through the probe retainer.

Each of the first clamp and the second clamp may be connected to thereceiver by a respective clamp arm, and may comprise a tab extendingfrom the clamp arm in a first direction, and a hook extending from theclamp arm in a second direction, the second direction being generallyopposite the first direction. The first clamp and the second clamp maybe connected to the receiver by respective flexible connections, eachflexible connection being movable to allow the respective tab to movetowards the receiver and the respective hook to move away from thereceiver to thereby release the respective hook from engagement with thesidewall. The flexible connections may be bendable clamp arms. Thesidewall may have one or more outwardly-extending lips at the proximalintroducer end, the one or more outwardly-extending lips having a firstportion positioned to be engaged with the respective hook of the firstclamp, and a second portion positioned to be engaged with the respectivehook of the second clamp.

The receiver may have a lock to selectively hold the navigation probeshaft against movement along the longitudinal axis. The lock may have afirst threaded member having an inner passage with a first taperedsurface; and a second threaded member having an outer body having asecond tapered surface that fits within the first tapered surface and aninner channel dimensioned to receive the navigation probe shaft; whereinrelative rotation between the first threaded member and the secondthreaded member moves the first tapered surface towards the secondtapered surface to compress the inner channel to hold the navigationprobe shaft. The second tapered surface may have one or more slotsextending along the longitudinal direction.

The first threaded member may have a hollow passage connected to movewith the first clamp and the second clamp, and the second threadedmember may have a knob portion connected to the second tapered surface.The probe retainer may have one or more hooks positioned to engage a lipon the second threaded member to inhibit the second threaded member fromseparating from the first threaded member.

The second threaded member may be connected to move with the first clampand the second clamp, and the first threaded member may be a knobportion connected to the first tapered surface. The probe retainer mayhave one or more hooks positioned to engage a lip on the first threadedmember to inhibit the first threaded member from separating from thesecond threaded member.

The receiver may have a receiver passage extending along thelongitudinal axis from a proximal receiver passage end located inrelative proximity to the proximal introducer end, to a distal receiverpassage end located in relative proximity to the distal introducer end,and the receiver comprises one or more slots along the longitudinal axisat the distal receiver passage end. An inner diameter of the receiverpassage may taper to a smaller size at the distal receiver passage end.

The introducer may have a probe receptacle located at the distalintroducer end, the probe receptacle extending along the longitudinalaxis within the introducer passage from a proximal receptacle end to adistal receptacle end, the probe receptacle having an inner surfacehaving a first lateral size in the lateral direction at the proximalreceptacle end and a second lateral size in the lateral direction at thedistal receptacle end, the first lateral size being greater than thesecond lateral size. The probe receptacle may have a distal receptacleopening passing through the distal receptacle end and forming a firstfluid flow path between the inner surface and an exterior of thesidewall at the distal introducer end. At least a portion of the probereceptacle may be spaced from the sidewall in the lateral direction by agap. The probe receptacle may have at least one opening at a locationbetween the receptacle proximal end and the receptacle distal endforming a fluid communication path between the inner surface and thegap.

The introducer may have an introducer tip opening forming a fluid flowpath through the sidewall at the distal introducer end.

The foregoing summary of the invention provides a variety of exemplaryembodiments that may be used in any suitable combination, and is notintended to impose any limitations upon the invention recited in theclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the exemplary embodiments may be understood byreference to the attached drawings, in which like reference numbersdesignate like parts. The drawings are exemplary, and not intended tolimit the claims in any way.

FIG. 1 is an example of a prior art delicate tissue retractor system.

FIG. 2A is a cutaway side view of a first embodiment of an introducerhaving a guidance probe receptacle.

FIG. 2B is a cutaway side view of the distal tip of the embodiment ofFIG. 2A, shown at a slight oblique angle.

FIG. 3A illustrates a distal tip of another embodiment of an introducerhaving a guidance probe receptacle, as viewed from inside theintroducer.

FIG. 3B is a cutaway side view of the distal tip of the embodiment ofFIG. 3A.

FIG. 4A illustrates a distal tip of another embodiment of an introducerhaving a guidance probe receptacle, as viewed from inside theintroducer.

FIG. 4B is a cutaway side view of the distal tip of the embodiment ofFIG. 4A.

FIG. 5A illustrates a distal tip of another embodiment of an introducerhaving a guidance probe receptacle, as viewed from inside theintroducer.

FIG. 5B illustrates the embodiment of FIG. 5A, as viewed from outsidethe introducer.

FIG. 5C is a cutaway side view of the distal tip of the embodiment ofFIG. 5A, as shown along line 5C-5C.

FIG. 5D is a cutaway side view of the distal tip of the embodiment ofFIG. 5A, as shown along line 5D-5D.

FIGS. 6A-6D are cross-sectional side views of the distal tips of fourdifferent navigation probes.

FIGS. 7A-7B illustrate an embodiment of a centering device that may beused with embodiments of introducers.

FIGS. 8A-8B illustrate the embodiment of FIGS. 7A-7B in use.

FIGS. 9A and 9B are assembled and exploded views, respectively, of analternative embodiment of a centering device and probe retainer system.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the invention may provide various features to supplementor advance the state of the art of surgical introducers and retractorsystems. As used herein, the term “guidance system” is intended toinclude any system for assisting a surgeon with advancing the retractorsystem to the surgery site, and can include passive systems like guidewires, or active systems like navigation probes that are detected andtracked using a computerized telemetry system. The term “surgeon”includes anyone in the operation theater who might use or manipulate theintroducer system. Active probes can be tracked by various techniques,including: optically tracking a “starburst” or other marker mounted on aportion of the probe that remains visible during the procedure; directlymonitoring the probe's position using radiation imaging (e.g., X-ray) ormagnetic imaging; physically connecting the probe to a frame ofreference system to mechanically track the position of the probe; orother means or combinations of means, as known in the art. The terms“navigation” and “guidance” are used interchangeably herein. Embodimentsalso may be used with manual systems in which the surgeon moves theretractor system entirely by hand, or semi-automated or automatedsystems that operate under the surgeon's control or automaticallyadvance the retractor system to the surgery site without the surgeon'sintervention.

Embodiments may be used with dedicated systems that are designed anew,or with preexisting systems. For example, embodiments may be used withsystems like the one shown in FIG. 1 , such as by supplementing,modifying or replacing the introducer 102, or with other introducerassemblies, as will be appreciated by persons or ordinary skill in theart. The embodiments described herein may be used with a retractor 100as shown in FIG. 1 , or in other retractors. It will be readilyappreciated that the shape of the introducer can be modified to fit intoany conventional retractor, and the introducer also may be modified toconnect to the retractor (if necessary or desired) using any suitableclamp or other engagement mechanism. For example, embodiments may beused with small-scale versions of introducers like the one shown in FIG.1 , in which the embodiment optionally may be scaled down to allowvisibility into the retractor, but providing such visibility is notrequired in all embodiments.

The exemplary embodiments described herein are directed towardsintroducers for use in neurosurgery or other operations in and aroundthe brain or skull. However, uses in other parts of the body are alsopossible.

FIG. 2A shows an exemplary embodiment of an introducer 200 that isconfigured to be releasably retained inside a retractor 202 such asretractor 100 of FIG. 1 . The introducer 200 comprises a sidewall 204that extends from a proximal introducer end 206 to a distal introducerend 208. As used herein, “proximal” refers to the end that generallyfaces the surgeon in use, and “distal” refers to the end that is locatedtowards or inserted into the patient. When connected together, theproximal introducer end 206 may be located at or near a proximalretractor end, and the distal introducer end 208 extends beyond a distalretractor end. The retractor 202 preferably comprises a hollow tubularretractor passage extending along a longitudinal axis from a proximalretractor end to a distal retractor end, and is dimensioned to allowsurgical procedures to be undertaken therethrough.

The introducer sidewall 204 forms an introducer passage 210 that extendsalong a longitudinal axis 212 extending from the proximal introducer end206 to the distal introducer end 208. When assembled with the retractor202, a distal tip portion 214 of the introducer 200 extends beyond thedistal end of the retractor 202. Together, the distal tip portion 214and the retractor 202 form a generally smooth and continuous surface forgently displacing brain tissue or the like as the assembly is advancedinto the body. The distal tip portion 214 preferably is tapered with arounded (such as shown) or conical shape. A tip opening 216 may beprovided at or near the distal introducer end 208, as discussed in moredetail below. A lock (see, e.g., FIG. 1 ) may be provided to selectivelyhold the introducer 200 to the retractor 202.

The sidewall 204 preferably comprises a continuous wall surface suchthat the passage 210 has a closed outer perimeter, such as shown in FIG.1 . This can help prevent unwanted entry of body fluids and provide asmooth continuous surface for viewing through the sidewall 204 (if it istransparent) and for guiding instruments down the length of the passage210 without risk of displacement. However, one or more openings 218 maybe provided in the sidewall 204 in alternative embodiments.

The introducer sidewall 204 may have any suitable cross-sectionalprofile (i.e., profile in a plane orthogonal to the longitudinal axis212). For example, the sidewall 204 may be circular, elliptical, oval orotherwise generally curved (i.e., comprised entirely of curved surfacesand/or very short straight surfaces that effectively simulate asmoothly-curved shape). If desired, the cross-section may include one ormore rectilinear segments (e.g., a D-shape), or may be entirelyrectilinear (e.g., a square or triangular shape). The sidewall profilealso may taper to be larger at the proximal end than at the distal end,and preferably reduces at least slightly in size as it approaches thedistal introducer end 208. The outer surface of the sidewall 204 may beshaped to match the shape of a corresponding inner wall of the retractor202, but this is not strictly required. The introducer sidewall 204 alsopreferably has a generally consistent wall thickness along its length,which can facilitate manufacturing and provide a more suitable opticalpath for viewing through the sidewall 204. It will be understood thatcross-sectional shape of the passage 210 will be defined by the shape ofthe sidewall 204, and therefore the foregoing discussion about theshapes of the sidewall 204 applies also the shape of the passage 210.

The introducer 200 preferably is transparent at least at the distal end206, and more preferably at the distal tip portion 214, and morepreferably along most or the full length of the sidewall 202. Thetransparent portion allows the surgeon to visualize underlying tissuewhile advancing the introducer 200 through brain tissue or the like,which can provide significant benefits during surgery. However, inalternative embodiments, the introducer 200 may be opaque. Suitablematerials for the introducer 200 include polycarbonate and other kindsof plastic, metals such as aluminum, stainless steel or titanium, glassor ceramic, or other materials that are biocompatible or that can betreated via coatings or the like to be biocompatible.

The passage 210 is sized to accommodate a navigation probe 220. Theprobe 220 comprises a shaft 222 that extends from a distal probe tip 224to a proximal probe end 226. The probe 220 includes a navigation element228 that is operatively associated with a navigation system to track theposition of the probe 220 and convey this information to the surgeonduring the course of surgery.

The navigation element 228 may comprise, for example, an optical array(e.g. three or more lights or reflectors in a predetermined physicalpattern) that provides a three-dimensional registration of the positionof the probe tip 224 when viewed by a corresponding navigation camerasystem. Such an array may be mounted to the proximal probe end 226 orelsewhere where it can be viewed by the navigation cameras. The need fora line-of-sight between the optical array and the cameras is likely torequire the navigation element 228 to be positioned outside theintroducer 200. Alternatively, the navigation element 228 may comprise amagnetic element that can be tracked by a corresponding magnetictracking system. In this case, it may not be necessary to position thenavigation element 228 outside the introducer 200. Other alternatives ofnavigation elements 228 will be apparent to persons of ordinary skill inthe art in view of the present disclosure. Examples of navigation probes220 and corresponding tracking systems are provided by StrykerNavigation of Kalamazoo, Mich., U.S.A.; Brainlab AG of Feldkirchen,Germany; Synaptive Medical of Toronto, Ontario; and Medtronic ofMinneapolis, Minn., U.S.A.

The introducer passage 210 is significantly larger in the lateraldirection (i.e., perpendicular to the longitudinal axis 212) than theprobe shaft 222. This may allow the surgeon to visualize down the lengthof the passage 210 without her vision being unduly obstructed by theprobe 220. This also may allow the surgeon to insert other instrumentssuch as an endoscope or aspiration tube into the passage 210 while theprobe 220 remains in place, and so on. As a consequence of theirdisparate relative sizes, the sidewall 204 does not hold the navigationprobe shaft 222 against lateral movement within the passage 210. Itexpected that some lateral movement of the probe shaft 222 within thepassage 210 will not critically affect proper navigation, but it isbelieved to be more important to assure continuous proper registrationbetween the distal probe tip 224 and a fixed location at the distalintroducer end 208. For example, maintaining the probe tip 224 withlittle or no deviation from the geometric center of the introducerprofile at the distal introducer end 208 is expected to providesufficient registration for accurate navigation, even if the proximalend of the shaft 222 might move laterally within the passage 210.

In the embodiment of FIGS. 2A and 2B, the probe tip 224 is maintained inregistration with the distal introducer end 208 by a probe receptacle230. The probe receptacle 230 preferably is located at the geometriccenter of the introducer profile at the distal introducer end 208 (e.g.,the geometric center of the ellipse if the distal introducer end 208 iselliptical), but this is not strictly required in all embodiments. Forexample, the receptacle 230 may be offset from the introducer's centralaxis.

The probe receptacle 230, in this embodiment, comprises a generallycircular receptacle wall 232 having an inner surface 236 that extendswithin the passage 210 from a distal receptacle end 240 to a proximalreceptacle end 234. The inner surface 236 tapers from a relatively largediameter at the proximal receptacle end 234 to a relatively smalldiameter at a distal receptacle end 240. The distal receptacle end maybe located at or near the distal introducer tip 208. The receptacle wall232 is sized to restrict the distal probe tip 224 from moving laterallybeyond a predefined range of movement. For example, the receptacle wall232 may restrict movement of the probe tip 224 to a range of less than 1millimeter (“mm”) in the lateral direction, or more preferably it may besized to restrict any movement in the lateral direction.

The diameter of the proximal receptacle end 234 may have any size, butpreferably is not so large as to significantly obstruct vision throughthe introducer 200, and not so small that it is overly difficult toposition the probe tip 224 within the receptacle 230 during surgery. Thereceptacle wall's tapered surface 236 helps guide the probe tip 224 tothe proper location within the receptacle 230, and the surface 236 mayhave a conical or curved profile as viewed from the lateral direction.The surface 236 also may have a region with a shape specificallyselected to match the shape of the probe tip 224. For example, if theprobe tip 224 is hemispherical, all or a portion of the surface 236 mayhave a matching shape. As another example, if the probe tip 224 iscylindrical (or has a hemispherical tip with a cylindrical bodyimmediately adjacent the tip), a distal portion of the surface 236 mayhave a matching cylindrical shape. Other alternatives will be apparentto persons of ordinary skill in the art in view of the presentdisclosure.

The receptacle wall 232 also may be shaped and sized to hold the probetip 224 in close proximity to the distal introducer end 208. For examplethe distance from the distal introducer end 208 to the probe tip, asmeasured along the longitudinal axis 212, preferably is less than 5.0mm, and more preferably less than 1.0 mm, and most preferably 0.5 mm orless. Where the probe tip 224 is at 1.0 mm or less from the distalintroducer end 208 it may not be necessary to attempt to correct forthis amount of displacement for purposes of navigating into the braintissue, as this is expected to be within the normal amount of deviationof brain tissue movement within the skull. It is preferred, but notstrictly required, that the probe tip 224 does not protrude beyond thedistal introducer end 208.

The introducer tip opening 216 (if one is provided) may be locatedwithin the probe receptacle 230 at the end of the receptacle wall 232,such as shown in FIG. 2B. Alternatively, the introducer tip opening 216may be located elsewhere in the distal introducer end 208 at a locationoutside the receptacle 230. The probe receptacle 230 also may includeone or more openings forming flow passages 238 to allow fluid to bypassthe receptacle wall 232; this feature can help ensure proper drainage offluids that might otherwise accumulate at the distal end of the passage210 at locations between the proximal receptacle end 234 and thesidewall 204. More specifically, a gap 242 may be provided between anouter wall 244 of the probe receptacle 230 and the introducer sidewall204, and fluid may accumulate in this gap 242 under some circumstances.The flow passages 238 are provided to allow fluid to exit the gap 242.

In use, the surgeon assembles the introducer 200 and retractor 202together, places the probe tip 224 into the receptacle 230, and usescomputer-aided navigation provided by the probe 220 to guide theassembly to the surgery site. During navigation, the probe 220 indicatesthe position of the distal introducer end 208 relative to the underlyingtissue via a computer screen overlay of a representation of the probeand a representation of the tissue. Throughout the process, the surgeonpreferably can inspect the tissue through transparent walls of theintroducer 200 and retractor 202, and can periodically remove the probe220 as necessary to obtain a better visual image or to performintermediate procedures such as suctioning fluid and the like.

FIGS. 3A and 3B illustrate another embodiment of an introducer 300. Forsimplicity, only the portion of the introducer 300 located near thedistal introducer end 302 is shown in these illustrations, and it willbe understood that other features of the introducer 300 such as theremainder of the internal passage and other features describedpreviously herein will be connected to the illustrated portion. In thisembodiment, introducer 300 has a probe receptacle 304 that is suspendedwithin the introducer 300 by a number of supports 306.

The probe receptacle 304 may be located on the introducer's centerline,which is parallel to the introducer's longitudinal axis 308, but otherlocations are possible. The probe receptacle 304 preferably comprises areceptacle wall 310 (which is circular, but can have other shapes) thatextends from a proximal receptacle end 312 to a distal receptacle end314. The receptacle wall 310 has an inner surface 316 that tapers from arelatively large size at the proximal receptacle end 312 to a relativelysmall size at the distal receptacle end 314. The inner surface 316 issized and shaped to retain the distal probe tip 224 to prevent the probetip 224 from moving laterally. For example, FIG. 3B shows the probe tip224 at a position shortly before it fully seats in the probe receptacle304, to more clearly show that the tapered inner surface 316 transitionsfrom a linearly tapering proximal surface portion 318 to a distalsurface portion 320 that is shaped to match the hemispherical shape ofthe probe tip 224. When fully seated, the probe tip 224 abuts the distalsurface portion 320 in something like a ball-and-socket arrangement,with the semi-hemispherical surface of the distal surface portion 320cupping and closely conforming to the hemispherical probe tip 224. Inother embodiments, the inner surface 316 may have other shapes toaccommodate different shapes and sizes of probe tip 224. For example, asimple conical shape can accommodate different probes having various tipdiameters.

The supports 306 are formed as planar ribs that radiate outward from theintroducer's centerline, and extend in parallel with the longitudinalaxis 308. In alternative embodiments, the supports 306 may be replacedby other shapes, such as blocks, pillars, and so on.

The probe receptacle 304 may be positioned adjacent to an introducer tipopening 322 that passes through the distal introducer end 302. Theintroducer tip opening 322 and probe receptacle 304 are positioned suchthat fluid located in a gap 328 between the probe receptacle's outerwall 330 and the sidewall 204 can pass through the introducer tipopening 322 without passing through the probe receptacle 304. Thus,fluid can flow through the introducer tip opening 322 even when theprobe tip 224 is installed within the probe receptacle 304. The probereceptacle 304 also may include a distal receptacle opening 324 passingthorough the distal receptacle end 314, which provides an additionalflow path when the probe is not installed in the probe receptacle 304and prevents fluid from pooling in the probe receptacle 304.

In the illustrated embodiment, the distal receptacle end 314 extendsinto the introducer tip opening 322, such that it lies at or near theplane of the distal introducer end 302. Thus, the introducer tip opening322 is formed as an annular passage that surrounds the probe receptacle304, and the supports 306 bridge the gap between the distal introducerend 302 and the probe receptacle 304. The supports 306 may includearched voids 326 to help reduce any disruption in the flow through theintroducer tip opening 322 that the supports 306 might otherwise cause.

The placement of the distal receptacle end 314 within the introducer tipopening 322 can place the probe tip 224 as close as possible to thedistal introducer end 302. This simplifies the registration between theprobe 220 and the introducer 300 because there is very little offsetbetween their distal ends. However, this arrangement is not required inall embodiments. For example, the probe receptacle 304 may be movedfurther in the proximal direction (i.e., back into the introducerpassage) to allow more fluid flow capacity through the introducer tipopening 322, to make the introducer tip opening 322 smaller, and forother reasons. If the offset between the probe tip 224 and the distalintroducer end 302 is significant, the computer system associated withthe probe 220 can be programmed to account for this offset whenindicating the position of the introducer 300 to the surgeon, as knownin the art.

The receptacle 304 is preferably positioned and sized such that at leasta portion of the introducer sidewall 204 at the distal introducer end302 is visible to the surgeon while the probe tip 224 is installed inthe receptacle 304. For example, a pair of transparent faces 332 of thesidewall 204 (which may be flat as shown or curved) may be visiblearound the receptacle 304 and probe 220. The surgeon can visuallyinspect the underlying tissue even while the probe 220 is in place, andcan move the probe shaft 222 around within the passage 210 to alter herview without displacing the probe tip 224 from the receptacle 304.

FIGS. 4A and 4B illustrate another embodiment of an introducer 400. Aswith FIGS. 3A and 3B, only the region of the introducer 400 adjacent thedistal introducer end 402 is shown. It will be understood that otherfeatures of the introducer 400 such as the remainder of the internalpassage and other features described previously herein will be connectedto the illustrated portion. In this embodiment, the introducer 400 has aprobe receptacle 404 that includes a portion that is suspended withinthe introducer 400 by a number of supports 406. The probe receptacle 404may be located on the introducer's centerline, which is parallel to theintroducer's longitudinal axis 408, but other locations are possible.

The probe receptacle 404 preferably comprises a receptacle wall 410(which is circular, but can have other shapes) that extends from aproximal receptacle end 412 to a distal receptacle end 414. Thereceptacle wall 410 has an inner surface 416 that tapers from arelatively large size at the proximal receptacle end 412 to a relativelysmall size at a the distal receptacle end 414. The inner surface 416 issized and shaped to retain the distal probe tip 224 to prevent the probetip 224 from moving laterally when the probe tip 224 is fully seated inthe probe receptacle 404. The inner surface 416 may be similar inconstruction to the probe receptacle 304 described in relation to FIGS.3A and 3B, or have other shapes configured to retain the probe tip 224.For example, the inner surface 416 may comprise a proximal portionadjacent the proximal receptacle end 412 having a first angle θ1relative to the longitudinal axis 408 in the range of 20⁰−30° (e.g.,250), an intermediate portion located distally from the upper portionhaving a second angle θ2 relative to the longitudinal axis 408 in therange of 50−15° degrees (e.g., 10 ⁰), and a distal portion locateddistally from the intermediate portion having a hemispherical orsemi-hemispherical shape having a radius r in the range of 0.3-0.8 mm.This arrangement is expected to provide simple and repeatableinstallation of the probe tip 224 into the receptacle 404, and provide adistinct feel to indicate when the probe tip 224 is fully seated.

The probe receptacle 404 is positioned adjacent to an introducer tipopening 418 that passes through the distal introducer end 402. Theintroducer tip opening 418 and probe receptacle 404 are positioned suchthat fluid can pass through the introducer tip opening 418 withoutpassing through the proximal receptacle end 412. This allows fluidlocated in a gap 426 between the probe receptacle's outer wall 428 andthe introducer sidewall 204 to flow through the introducer tip opening418 when the probe tip 224 is installed within the probe receptacle 404.In the shown embodiment, the outer wall 428 is shown being spaced fromthe sidewall 204 around its entire perimeter, but it will be appreciatedthat the outer wall 428 may merge with the sidewall 204 at somelocations (such as when the introducer profile is a narrow ellipse oroval, and the receptacle 404 has a circular profile).

The probe receptacle 404 also may include a distal receptacle opening420 passing thorough the distal receptacle end 414, to provide anadditional flow path when the probe is not installed in the probereceptacle 404, and prevent fluid from pooling in the probe receptacle404. The distal receptacle end 414 may extend into the introducer tipopening 418, such that it lies at or near the plane of the distalintroducer end 402. In this case, the introducer tip opening 418 may beformed as an annular passage that surrounds the probe receptacle 404with the supports 406 bridging the gap between the distal introducer end402 and the probe receptacle 404. The supports 406 may include archedvoids to help reduce any disruption in the flow through the introducertip opening 418 that the supports 406 might otherwise cause. As with theembodiment of FIGS. 3A and 3B, locating the distal receptacle end 414within the introducer tip opening 418 can place the probe tip 224 asclose as possible to the distal introducer end 402. However, thisarrangement is not required in all embodiments.

In this embodiment, the proximal receptacle end 412 is larger in thelateral direction (i.e., perpendicular to the longitudinal axis 408)than the introducer tip opening 418. This provides a relatively largeprobe receptacle 404 to help guide the probe 220 into place, whilekeeping the size of the introducer tip opening 418 relatively small tohelp prevent the possibility of brain tissue or other delicate tissuebeing damaged by being forced into or cut by the edges of the introducertip opening 418. FIG. 4B shows how this configuration helps guide theprobe tip 224 into the probe receptacle 404, even when it starts at alocation that is significantly offset from the probe receptacle'scenterline (which, in this example, is collinear with the geometriccenter of the introducer 400).

Where the proximal receptacle end 412 is larger than the introducer tipopening 418, it may be particularly favorable to provide additionalprovisions for assuring suitable flow through the introducer tip opening418. To this end, the probe receptacle 404 may include one or more(preferably three) openings at a location between the proximalreceptacle end 412 and the distal receptacle end 414 to allow fluid toflow to the introducer tip opening 418 without passing through theproximal receptacle end 412. Such openings may be, for example, slots422 extending inward from the outer surface of the probe receptacle 404to the introducer tip opening 418. These slots 422 allow fluid to drainfrom the most distal parts of the introducer passage to prevent poolingaround the outer perimeter of the probe receptacle 404 at the distal endof the introducer. The slots 422 in the shown embodiment extend in thelongitudinal direction from the proximal receptacle end 412 to a portionof the sidewall 204 located adjacent the distal receptacle end 414, butother embodiments may have slots having different lengths in thelongitudinal direction.

Each slot 422 may terminate at its inner end at an annular passage 424that overlies the introducer tip opening 418. The annular passage 424passes through the inner surface 416 of the receptacle 424 and extendsto the introducer tip opening 418, and is expected to help redistributefluids passing through the introducer tip opening 418 into a moreuniform and less restricted flow. The supports 406 bridge and interruptthe annular passage 424 to join the proximal receptacle end 412 to thedistal receptacle end 414 and to suspend the distal receptacle end 414at the introducer tip opening 418. The slots 422 and annular passage 424are sized to prevent the probe tip 224 from entering them (e.g., byhaving a 0.5 mm maximum width if the smallest probe tip 224 to be usedis 0.8 mm or larger).

As with the other embodiments, the receptacle 404 is preferablypositioned and sized such that a transparent portion of the introducersidewall 204 at the distal introducer end 402 is visible to the surgeonwhile the probe tip 224 is installed in the receptacle 404, to allowvisualization of the underlying tissue while the probe 220 is in place.

FIGS. 5A through 5D illustrate another embodiment of an introducer 500,of which only the region of the introducer 500 adjacent the distalintroducer end 502 is shown. As with the previous embodiments, it willbe understood that other features of the introducer 500 will beconnected to the illustrated portion. In this embodiment, the introducer500 has a probe receptacle 504 having primary supports 506 joining aproximal receptacle end 508 to a distal receptacle end 510. The distalreceptacle end 510 is adjacent (and preferably within) an introducer tipopening 512. The proximal receptacle end 508 is larger, in a directionperpendicular to the longitudinal axis 514 of the introducer 500, thanthe introducer tip opening 512. The structure of this probe receptacle504 is similar to the one illustrated in FIGS. 4A and 4B, and caninclude the same variations and features (e.g., a distal receptacleopening, etc.). The description of FIGS. 4A and 4B applies equally tothe embodiment of FIGS. 5A-5D.

The embodiment of FIGS. 5A-5D differs from FIGS. 4A and 4B in thatsecondary supports 516 joining the proximal receptacle end 508 to thedistal receptacle end 510 are provided on either side of each slot 518.The secondary supports 516 preferably have larger voids at their distalends to provide a more continuous flow passage adjacent the introducertip opening 512. For example, the primary supports 506 may be connectedto the distal receptacle end 510 by ribs 520 having a lower end locatedwithin or near the introducer tip opening 512, while the secondarysupports 516 are connected to the distal receptacle end 510 by ribs 522that are spaced above the introducer tip opening 512, such as best shownin FIG. 5C. This arrangement provides additional structures to supportthe distal receptacle end 510 and to prevent a surgeon from lodging theprobe tip 224 in the slots 518 or the gaps between the proximalreceptacle end 508 and the distal receptacle end 510, while stillproviding an annular passage 524 (FIG. 5B) (which may be interrupted atsome locations by the primary support ribs 520) at the introducer tipopening 512 to allow relatively free flow therethrough. Openings 526,located between the secondary supports 516 and primary supports 506,provide flow passages that pass through the inner surface of the probereceptacle 504 and extend along the longitudinal axis 514 to theintroducer tip opening 512, to allow vertical fluid flow at variouslocations. As with the previous embodiments, fluid located in a gap 528between the probe receptacle's outer wall 530 and the introducersidewall 204 can flow through the introduced tip opening 512 withouthaving to pass through the proximal introducer end 508, which helpsreduce any flow restriction that might be caused by the probe tip 224.

It is also contemplated that the primary supports 506 may be constructedlike the shown secondary supports 516 (i.e., with high arched ribs 522joining to the distal receptacle end 510). However, the lower ribs ofthe primary supports 506 such as shown in FIGS. 5A-5D may be helpful toadd strength and to prevent tissue from entering the introducer tipopening 512. Alternatively, the secondary supports 516 can bestructurally identical to the primary supports 506, if it is found thatthe added support is desirable and the restriction to flow through theintroducer tip opening 512 is not unduly compromised. Other alternativeswill be apparent to persons of ordinary skill in the art in view of thepresent disclosure.

The probe receptacle of any given embodiment may have any suitable shapeto fit any desired navigation probe. The probe receptacle may beconfigured to fit one particular kind of probe, or it may be configuredto retain a number of different navigation probes. For example, a probereceptacle as described above with reference to FIGS. 2A-5D may beconfigured to interchangeably receive any one of four or more differentprobes such illustrated in FIGS. 6A to 6D. A first probe 600 has a tipdiameter D of 1.0 mm and a taper angle θ of approximately 6.00. A secondprobe 602 has a tip diameter D of 0.8 mm and a taper angle θ ofapproximately 7.50. A third probe 604 has a tip diameter D of 1.0 mm anda taper angle θ of approximately 18.00. A fourth probe 606 has a tipdiameter D of 1.0 mm and a 1.0 mm diameter cylindrical shaft 608extending proximally from the tip. Each of these probes can be insertedwith the probe tip seated at the distal end of the receptacle, within1.0 mm and more preferably within 0.5 mm of the distal introducer end,to hold probe tip against lateral movement.

The receptacle may be formed such that it is not likely for the surgeonto “wedge” the probe tip in place, as this may cause difficulty withremoving the probe. To this end, it is preferred for the taper angle ofthe receptacle's inner wall to not exactly match the taper angle of anyparticular probe tip in such a way to lock the two parts together. It isalso preferred for the material of the receptacle to be relatively hardto prevent it from deforming to allow the probe tip to become lodgedtherein. Polycarbonate plastic is expected to be suitable for thispurpose, but other materials may be used. Of course, a surgeon applyinga very large force on the probe might lodge it in the receptacleregardless of how the receptacle is designed, so it will be understoodthat these preferences are predicated on normal use of the instrumentand are not intended to set strict requirements for all embodimentsunder all circumstances.

Alternatively, the receptacle may be deliberately formed to tend tocapture the probe tip in place. For example, the probe tip may includean enlarged end that snaps into a corresponding shape within thereceptacle such that a force is required to remove the probe, or thereceptacle may include thin deformable ribs that tend to grip the tip ofthe probe. This may require more care when removing the probe, but addthe benefit of not requiring the surgeon to handhold the probe at alltimes.

The foregoing embodiments are expected to help surgeons use introducerand retractor systems with navigation systems. It is expected thatsurgeons will use the device by assembling the introducer with aretractor, placing the navigation probe in the introducer until the tipof the probe reaches the end of the probe receptacle, and then advancingthe three parts forward into the tissue as a unit. During the process,the surgeon can remove the probe to get a better view into theintroducer or to insert other instruments or devices into theintroducer. If desired, a clamp or other device may be provided to holdthe probe in place to free up the surgeon's hands for other tasks.Examples of clamps are disclosed in the incorporated references, butother mechanisms may be used. Other uses and methods will be apparent tothose of ordinary skill in the art in view of this disclosure.

The introducer tip opening may add significant benefits to the system,such as by allowing fluids to ventilate to prevent an excessiveaccumulation of pressure around the introducer, allowing removal offluids, and if the opening is large enough allowing resection or manualmovement of tissue adjacent the opening. The tip opening also may allowair to vent towards the tissue as the introducer is withdrawn from theretractor after the assembly is placed at the surgery site, which canhelp prevent the introducer from generating suction that pulls on thetissue as the introducer is withdrawn. Other benefits will be apparentin view of the this disclosure and with further use of the system.

While it is expected that the foregoing embodiments can be used“freehand” by simply placing the probe tip 224 into the probereceptacle, in some cases a surgeon may wish to lock the probe 220 inplace within the introducer 200. This may be accomplished by using aretaining mechanism, such as the exemplary probe retainer 700 shown inFIGS. 7A-8B.

The probe retainer 700 comprises a receiver 702 that is affixed to theintroducer 200 by a pair of clamps 704. The receiver 702 includes achannel 706 sized to receive a probe 220. The channel 706 preferably isa closed passage having a diameter suitable to accommodate a probe 220,but it may include a longitudinal slot or have a “C” or “U” shapedprofile, or the like, in other embodiments. The channel 706 has aproximal channel end 708 facing towards the surgeon, and a distalchannel end 710 that extends into the introducer 200. When the probeshaft 222 is located in the channel 706, the channel 706 limits and maycompletely restrict movement of the probe shaft 222 in the lateraldirection.

The receiver 702 may be configured to selectively lock the probe 220 inplace within the channel 706. For example, the proximal channel end 708may have a threaded outer surface 712 that is configured to engage acorresponding lock nut 714, and one or more cutout sections 716 passingthrough the proximal channel end 708. The threaded outer surface 712 andlock nut 714 are configured such that the lock nut 714 compresses thethreaded outer surface 712 as it is tightened onto the threaded outersurface 712, such as by providing one or both with a slight taper ormaking the lock nut's threads slightly smaller in diameter than thethreads on the outer threaded surface 712. The cutout sections 716provide reliefs to allow the threaded surface 712 to move inwards as thelock nut 714 is tightened. Thus, as the lock nut 714 is tightened on thethreaded outer surface 712, the threaded outer surface 712 movesradially inwards, and an inner surface 718 of the proximal channel end708 clamps against and secures the probe 220 in place. The receiver 702also may include one or more retaining lips 720 to prevent the lock nut714 from being fully removed from the receiver 702.

Other locking mechanisms may be used in other embodiments. For example,the lock nut 714 may be replaced by a band clamp, a set screw, or otherdevices. Examples of alternative locks are provided in the incorporatedreferences, and other options will be apparent to the person of ordinaryskill in the art in view of this disclosure.

In the shown embodiment, the receiver 702 may include a number of slots722 (e.g., three slots) that extend proximally from the distal channelend 710. The exemplary slots 722 extend longitudinally along thelongitudinal axis 212 of the assembly, but other orientations may beused (e.g. helical). The inner surface of the channel 706 is also may begently tapered such that the diameter of the channel 706 decreases as itapproaches the distal channel end 710. The final diameter of the channel706 at the distal channel end 710 may be slightly less than the largestdiameter probe 220 expected to be used with the device, such that theprobe 220 is slightly compressed by the receiver 702 at the distalchannel end 710. The slots 722 allow the channel 706 to flex outwards atthe distal channel end 710 to accommodate probes 220 of different sizes.This feature is expected to provide a useful slight retaining force, andmay help center the probe 220 within the channel 706.

The receiver also may be configured to direct the distal probe tip 224towards a receptacle (e.g., receptacle 230, 304, 404 or 504) as theprobe 220 is installed into the introducer 200. The foregoing taperedand slotted arrangement is expected to accomplish this by orienting thechannel 706 towards a corresponding receptacle at the distal introducertip, but other embodiments may use other configurations to do the samething. Preferably, the channel 706 extends in the longitudinaldirection, so that it prevents significant angulation of the probe 220within the channel 706 (i.e., it prevents angulation that could preventthe distal probe tip 224 from entering the receptacle). For example, thechannel 706 may have an inner diameter that is no more than 110% of thelargest probe diameter, and a length that is at least 300% and morepreferably at least 1000% of the largest probe diameter.

Despite the foregoing, in other embodiments the channel 706 may comprisea simple ring or passage that is not tapered and does not include slots,or the taper and slots may be replaced by a flexible diaphragm orcantilevered arms that help center the probe 220 within the channel 706.Other alternatives will be apparent to persons of ordinary skill in theart in view of the present disclosure.

The clamps 704 are attached to the receiver 702, and configured to holdthe receiver 702 at a fixed location relative to the introducer 200. Thereceiver 702 may be centered on the introducer 200, such as shown, or itmay be offset from the introducer's centerline. In this embodiment, theclamps 704 are connected to the receiver 702 by clamp arms 724 that areshaped to generally match the shape of the introducer sidewall 204 atthe proximal introducer end 206. Thus, each clamp arm 724 has an opening726 through which the surgeon can view into the introducer passage 210.

Each clamp 704 comprises a tab 728 that is shaped to receive a user'sfinger, and a hook 730 that is shaped to wrap around a corresponding lip800 (FIGS. 8A-B) on the introducer. The clamp arms 724 are locatedbetween the tab 728 and the hook 730. The clamp arms 724 and hooks 730are movable between a latched position in which the hooks 730 arerelatively close to one another, and an unlatched position in which thehooks 730 are relatively far from one another. In their latchedposition, the hooks 730 are spaced by a first distance at which theywrap around the corresponding lips 800 to secure the probe retainer 700to the introducer 200. The hook spacing in the latched position may beslightly greater than their natural resting position when not attachedto an introducer 200. Thus, when attached to the introducer 200, theclamp arms 724 may be under a slight bending force caused by flexing thehooks 730 from their resting position to their latched position. Thiscan help provide a stronger locking connection, and may reduce thelikelihood of shifting or moving when connected.

When the surgeon pinches the tabs 728 together, the clamp arms 724 flexand provide a fulcrum about which the hooks 730 rotate until they arelocated at a second distance from one another. In this position, thehooks 730 release the lips 800 and the probe retainer 70 can be removedfrom the introducer. The clamps 704 may be reinstalled onto theintroducer 200 by reversing this operation, and the hooks 730 mayinclude ramped surfaces to allow them to be snapped onto the lips 800simply by pressing the probe retainer 700 against the proximalintroducer end 206.

In the exemplary embodiment, there are two clamp arms 724, each of whichhas two spaced portions that surround an opening 726 to allowvisualization into the introducer 200. Each clamp arm 724 is connectedto the receiver 702 at two locations on opposite sides of the receiver702. The attachments between the receiver 702 and the clamp arms 724 mayhave buttresses 732 to increase the rigidity of the connection. This isexpected to help the clamp arms 724 flex in a more predictable mannerduring the detachment and installation process.

The foregoing clamp 704 arrangement is expected to provide simple andreliable engagement to selectively connect the probe retainer 700 to theintroducer 200. However, other embodiments may use different structuresto hold the probe in place. For example, the flexible clamp arms 724 maybe replaced by more rigid members having a mechanical pivot such as apivot pin or the like and a return spring to bias the hooks 730 to theclamped position. As another example, each clamp arm 724 may have asingle portion located on one side of the introducer 200, rather thantwo spaced portions, and the clamps 704 may be turned 90° relative tothe shown position such that the grip the introducer 200 from the siderather than from the top. Other alternatives will be apparent to personsof ordinary skill in the art in view of the present disclosure.

FIGS. 8A and 8B show the embodiment of FIGS. 7A-B as it appears wheninstalled on an exemplary introducer 200. The introducer 200 is shownassembled with a corresponding retractor 202. The introducer 200preferably includes a probe tip receptacle such as those describedpreviously herein, but it is also envisioned that the probe retainer 700may be used with introducers that do not have a probe tip receptacle,such as those discussed with reference to FIG. 1 . The assembly of theprobe retainer 700 and navigation probe 220 preferably can be removedfrom or installed into the introducer 200 without separating theintroducer 200 from the retractor 202. This provides rapid access to theintroducer interior, if necessary.

FIGS. 9A and 9B show another embodiment of a probe retainer 900. In thiscase, the probe retainer includes a receiver 902 that can be affixed toan by a pair of clamps 904. This embodiment is generally the same as theembodiment of FIGS. 7 through 8B. However, in this embodiment themechanism for locking the probe shaft in place is different. Thereceiver channel 906 is formed with a threaded proximal end 908, aconically tapered central portion 910, and a relatively narrow distalportion 912. The locking nut 914 comprises a proximal knob portion 916that is adapted for use by the surgeon (e.g., knurled, or otherwiseshaped to be engaged by fingers or a tool), a male-threaded centralportion 918, and a tapered conical distal end 920 having one or morelongitudinal slots 922. A central passage 924 passes through the lockingnut 914 to receive the probe shaft. The threads 918 of the locking nut914 are configured to thread into the threads 908 of the receiver 902,and the conical distal end 920 of the locking nut 914 is dimensioned tofit into the conical central portion 910 of the receiver 902. Thelocking nut 914 is advanced into the receiver 902 by rotating itrelative to the receiver 902. When the tapered end 920 of the lockingnut 914 engages the tapered central portion 916 of the receiver channel906, contact between the parts flexes the tapered end 920 radiallyinwards to compress against the probe shaft. Thus, the locking nut 914can cooperate with the receiver 902 to engage and hold the probe shaftat a fixed location.

The locking nut 914 may be retained by one or more features thatinterlock with the receiver 902. For example, the receiver 902 may haveone or more hooks 926 that surround a lip 928 that extends radially fromthe knob portion 916 of the locking nut 914. These retaining featuresinhibit the locking nut 914 from accidentally separating from thereceiver 902 when the locking nut 914 is fully-loosened. However, insome embodiments, the hooks 926 may be designed to be deformable toallow the locking nut 914 to be removed. Other alternatives andvariations will be apparent to persons of ordinary skill in the art inview of the present disclosure.

It will be appreciated that the foregoing embodiments may be modified invarious ways. As one example, features disclosed in one embodiment maybe used with any of the other embodiments. As another example, the probereceptacles described herein can be formed integrally with theintroducer by additive manufacturing or molding (the illustratedembodiments show various configurations in which conventional two-partinjection molding processes may be used to make the introducer and probereceptacle as a single integrally molded part), or formed separately andattached to the introducer. As another example, the probe receptacle mayhave any sidewall profile shape, rather than the generally circularshapes shown in the embodiments. The probe receptacles also may have anycombination of conical, cylindrical, hemispherical, or other shapes. Itis also envisioned that the probe receptacle may have openings such asthe flow passages of FIG. 2B and slots of the later embodiments, evenwhen the introducer does not have an introducer tip opening, which canbe beneficial to displace fluid from the receptacle to allow free entryof the probe tip. Other alternatives will be apparent to persons ofordinary skill in the art in view of the present disclosure.

The present disclosure describes a number of new, useful and nonobviousfeatures and/or combinations of features that may be used alone ortogether. The embodiments described herein are all exemplary, and arenot intended to limit the scope of the inventions. It will beappreciated that the inventions described herein can be modified andadapted in various and equivalent ways, and all such modifications andadaptations are intended to be included in the scope of this disclosureand the appended claims.

We claim:
 1. An introducer system for use with a navigation probe havinga navigation element and a navigation probe shaft having a probediameter and terminating at a distal probe tip, the introducer systemcomprising: an introducer having a sidewall extending along alongitudinal axis and forming an introducer passage extending from aproximal introducer end to a distal introducer end, the introducerpassage having a first diameter in a lateral direction that isorthogonal to the longitudinal axis; and a probe retainer removablyconnected to the proximal introducer end, the probe retainer comprising:a receiver having a receiver passage configured to receive thenavigation probe shaft, the receiver passage having a second diameter inthe lateral direction that is less than the first diameter and less thanthe probe diameter, the second diameter being sized to limit movement ofthe navigation probe shaft in the lateral direction, a lock movablebetween a first position in which the lock allows the navigation probeshaft to be inserted through the receiver while the probe retainer isconnected to the proximal introducer end, and a second position in whichthe lock allows the navigation probe shaft to be removed from thereceiver while the probe retainer is connected to the proximalintroducer end.
 2. The introducer system of claim 1, wherein the proberetainer comprises a first clamp and a second clamp, the first clamp andthe second clamp being connected to the receiver with the receiverlocated between the first clamp and the second clamp, each of the firstclamp and the second clamp being selectively engageable with respectiveportions of the sidewall to hold the receiver at a fixed locationrelative to the introducer.
 3. The introducer system of claim 2, whereineach of the first clamp and the second clamp is connected to thereceiver by a respective clamp arm, each clamp arm having an openingtherethrough, the opening being aligned with the introducer passage toform a respective visual path through the probe retainer.
 4. Theintroducer system of claim 2, wherein each of the first clamp and thesecond clamp is connected to the receiver by a respective clamp arm, andcomprises a tab extending from the clamp arm in a first direction, and ahook extending from the clamp arm in a second direction, the seconddirection being generally opposite the first direction.
 5. Theintroducer system of claim 4, wherein the first clamp and the secondclamp are connected to the receiver by respective flexible connections,each flexible connection being movable to allow the respective tab tomove towards the receiver and the respective hook to move away from thereceiver to thereby release the respective hook from engagement with thesidewall.
 6. The introducer system of claim 2, wherein the first clampand the second clamp comprise respective hooks extending towards thereceiver, and the respective portions of the sidewall comprise lipsextending from an outer surface of the introducer away from thereceiver, wherein the hooks and lips are positioned such that each hookselectively engages a respective lip to hold the receiver at the fixedlocation relative to the introducer.
 7. The introducer system of claim1, wherein the receiver passage extends along the longitudinal axis froma proximal receiver passage end located in relative proximity to theproximal introducer end, to a distal receiver passage end located inrelative proximity to the distal introducer end.
 8. The introducersystem of claim 7, wherein lock comprises: a first member surroundingthe receiver passage and having external threads; a second membersurrounding the receiver passage and having internal threads; whereinthe first member is rotatable relative to the second member to engagethe external threads with the internal threads to thereby lock thenavigation probe shaft relative to the receiver.
 9. The introducersystem of claim 8, wherein the first member is fixed to the receiver andthe second member is movable relative to the receiver.
 10. Theintroducer system of claim 8, wherein the second member is fixed to thereceiver and the first member is movable relative to the receiver. 11.The introducer system of claim 8, wherein: at least one of the firstmember and the second member comprises an inner channel dimensioned toreceive the navigation probe shaft; at least one of the first member andthe second member comprises a tapered surface; and the first member ismovable relative to the second member between an unlocked position inwhich the tapered surface does not compress the inner channel againstthe navigation probe shaft, and a locked position in which the taperedsurface compresses the inner channel against the navigation probe shaftto thereby lock the navigation probe shaft relative to the receiver. 12.The introducer system of claim 11, wherein the inner channel comprisesone or more slots extending along the longitudinal direction.
 13. Theintroducer system of claim 12, wherein the inner channel comprises anouter tapered surface.
 14. The introducer system of claim 8, wherein oneof the first member and the second member is fixed to the receiver, andthe other of the first member and the second member is movable relativeto the receiver, and wherein the receiver further comprises a retainerpositioned to prevent the other of the first member and the secondmember from being removed from the receiver.
 15. The introducer systemof claim 14, wherein the retainer comprises one or more hooks positionedto engage a lip on the other of the first member and the second member.16. The introducer system of claim 1, wherein the introducer comprises aprobe receptacle located at the distal introducer end, the probereceptacle extending along the longitudinal axis within the introducerpassage from a proximal receptacle end to a distal receptacle end andbeing configured to hold the distal probe tip at a single fixed locationrelative to the introducer when the distal probe tip is fully insertedinto the probe receptacle.
 17. The introducer system of claim 16,wherein the introducer and probe retainer are reconfigurable between: afirst configuration in which the probe retainer is attached to theintroducer, the navigation probe shaft is located in the probe retainerand fixed in the lateral direction, and the distal probe tip is locatedin the probe receptacle and fixed in the lateral direction within theprobe receptacle; and a second configuration in which the probe retaineris not attached to the introducer, the navigation probe shaft is movablein the lateral direction within the introducer passage, and the distalprobe tip is fixed in the lateral direction within the probe receptacle.18. A surgical navigation probe retainer comprising: a receiver having areceiver passage extending in a longitudinal direction and configured toreceive a navigation probe shaft and limit movement of the navigationprobe shaft in a lateral direction that is perpendicular to thelongitudinal direction; one or more clamps extending from the receiverand configured to selectively secure the receiver to a surgicalintroducer; and a lock movable between a first position in which thelock allows the navigation probe shaft to move relative to the receiveralong the longitudinal direction and a second position in which the lockprevents the navigation probe from moving relative to the receiver alongthe longitudinal direction, wherein the lock comprises: a first membersurrounding the receiver passage and having a first threaded surface,and a second member surrounding the receiver passage and having a secondthreaded surface, wherein the first member is rotatable relative to thesecond member to engage the first threaded surface with the secondthreaded surface to thereby move the lock between the first position andthe second position.
 19. The surgical navigation probe retainer of claim18, wherein the first member is fixed to the receiver and the secondmember is movable relative to the receiver, and the probe retainerfurther comprises a retainer positioned to prevent the second memberfrom separating from the receiver.
 20. The surgical navigation proberetainer of claim 19, wherein at least one of the first member and thesecond member comprises an inner channel dimensioned to receive thenavigation probe shaft; at least one of the first member and the secondmember comprises a tapered surface; and when the lock is in the firstposition, the tapered surface does not compress the inner channelagainst the navigation probe shaft, and when the lock is in the secondposition, the tapered surface compresses the inner channel against thenavigation probe shaft to thereby lock the navigation probe shaftrelative to the receiver.
 21. The surgical navigation probe retainer ofclaim 20, wherein the inner channel comprises one or more slotsextending along the longitudinal direction.
 22. The surgical navigationprobe retainer of claim 21, wherein the inner channel comprises an outertapered surface.
 23. The introducer system of claim 1, furthercomprising a retractor comprising a hollow tubular retractor passageextending from a proximal retractor end to a distal retractor end, theretractor being configured to selectively receive the introducer withinthe hollow tubular retractor passage with a portion of the introducerend extending from the distal retractor end, and wherein the portion ofthe distal intruder end protruding from the distal retractor end tapersto the distal introducer end.